Molecular characterization of nucleocytosolic O-GlcNAc transferases of Giardia lamblia and Cryptosporidium parvum.
O-Linked N-acetylglucosaminyltransferase (OGT) catalyzes the transfer of a single GlcNAc to the Ser or Thr of nucleocytoplasmic proteins. OGT activity, which may compete with that of kinases, is involved in signaling in animals and plants, and abnormalities in OGT activities have been associated with type 2 diabetes. Here, we show that ogt genes that predict enzymes with characteristic tetratricopeptide repeats and a spindly domain are present in some protists (Giardia, Cryptosporidium, Toxoplasma, and Dictyostelium) but are absent from the majority of protists examined (e.g., Plasmodium, Trypanosoma, Entamoeba, and Trichomonas). Similarly, ogt genes are present in some fungi but are absent from numerous other fungi, suggesting that secondary loss is an important contributor to the evolution of ogt genes. Nucleocytosolic extracts of Giardia and Cryptosporidium show OGT activity, and recombinant Giardia and Cryptosporidium OGTs are active in yeast and bacteria, respectively. These results suggest the possibility that O-GlcNAc modification of nucleocytosolic proteins also has function(s) in simple eukaryotes.
Banerjee
Sulagna
S
Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, MA 02118, USA.
Robbins
Phillips W
PW
Samuelson
John
J
D000818:Animals; D002384:Catalysis; D016785:Cryptosporidium parvum / Q000201:enzymology* / Q000235:genetics; D016829:Giardia lamblia / Q000201:enzymology* / Q000235:genetics; D017351:N-Acetylglucosaminyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D015800:Protozoan Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology
D009687:Nuclear Proteins; D015800:Protozoan Proteins; D011994:Recombinant Proteins; D017351:N-Acetylglucosaminyltransferases